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HomeMy WebLinkAboutMemoLandscapeOptions3.14.11 Landfill 444 Cedar Street, Suite 1500 Saint Paul, MN 55101 (651) 292-4400 (651) 292-0083 Fax www.tkda.com MEMORANDUM To: Ryan W. Stempski, P.E. Reference: Landfill Project Landscape Options Proj. No.: 14816.001 From: Sherri Buss, RLA Routing: Date: March 14, 2011 Three options for landscaping the depressional area and roadway areas adjacent to the MPCA landfill are attached, and identified as Border Option A, B and C. The seed mix options for the lower areas and slopes are the same for all three options; the entry area plantings offer different approaches. This memo discusses the options. Seed Mixes for the Lower Area and Slopes Two options are suggested for the flat, depressional area and surrounding slopes, depending on desired use and appearance:  Option1: Use a native grass and wildflower (forb) mix. o Use a short/dry native mix in the lower area, and a mid-height/mesic mix on the slopes and in the ponding area. The short/dry mix includes plants that are typically 6” to 1 foot in height; the mid-height mix would include species 2-3 feet in height. Portions of the area could be mowed, to allow for casual recreational use, such as dog-walking, Frisbee, etc. Suitable mixes would include MnDOT 330 grass mix (short mix) plus forbs mix and 340 grass mix (mid-height) plus forbs mix; or short/dry and mesic native grass and wildflower mixes from a vendor such as Prairie Restorations. o The City should complete maintenance (2-3 mowings per year) as prescribed in the MnDOT Seeding Manual for native mix establishment, or contract with the seed vendor for on-going maintenance that would include occasional mowing and controlled burns to manage weeds.  Option 2: Low-mow grass mix o If a “turf” mix is desired to allow for more recreational use and a more formal appearance, the lower area could be planted with a low-mow turf mix, such as MnDOT 260 Commercial Turf or a “no-mow” mix from a vendor such as Prairie Nursery. These mixes grow to 4-6 inches tall, and may be mowed or not mowed. From a distance, the mix looks like a lawn, but requires less mowing. o Mowing could be completed as often as desired to control weeds. o The native mid-height/mesic mix recommended above could be seed on the slopes and in the “ponding” area in the southeast corner. Page 2 Options A-C for the Area along the Roadway and Entry Three options are identified for the area along the roadway and entry road, identified as Border Options A, B and C on the sheets attached. The shrubs and trees are planted in casual groups, rather than in the straight- line configuration used in the MPCA plan. If a few shrubs fail to survive or are eaten by deer, the loss will be less obvious in the more casual arrangement than it might be in the “row” planting. The groups were drawn to generally follow the gradual contours on the site. Options A and B include a larger number of shrubs than the original MPCA plan, because the plants selected are shorter and do not spread as much horizontally as the 10-12 foot plant materials shown in the MPCA plan. The numbers of trees and shrubs suggested in Option C are similar to the numbers suggested in the MPCA plan. The shrubs, grasses, and flowers should be surrounded by a shredded bark mulch, 4-5” deep, to minimize weeds. The mulch would need to be replaced every few years until the shrubs and other plants are mature. The grass mix would require 2-3 mowings per year until established, and then mowing once per year would be helpful to manage weeds.  Option A o Option A uses a mixture of native shrubs, grasses, and flowers as a roadway border, with a mid-height grass mix between the border and the depressional area. o The shrubs and grasses are up to six feet in height. The mix includes species that would flower in the spring and summer, and grasses and shrubs that have good fall color. The grasses would remain attractive in the winter. Most of the species offer food for birds (seeds and fruits). o Scattered groups of oaks and taller shrubs (6-10’ in height) have been added along the southern boundary with the landfill, to create a visual separation. Scattered groups of bur and white oaks have been added in the entry area and along the slopes to “frame” the views of the area. o The border is designed to be a colorful entry that will not block views into the site.  Option B o Option B uses all shrubs in the border, including some evergreen shrubs, to provide more winter interest. All shrubs are less than six feet tall at maturity, to preserve the view into the site. o Seeding and boundary options are similar to Option A.  Option C o Option C is a “savanna” planting, with groves of shrubs and trees scattered within a native grass planting. The recommended shrubs are natives that provide food for birds, and spring/summer/fall interest, with grasses providing the main interest in the winter. The mix of scattered shrubs and grasses would preserve the views into the site. o Seeding and boundary options are similar to Option A, with the mid-height native grass mix extending to the roadway, and planted at intervals with groups of trees and shrubs.